where \(\Omega \)  is the image domain.
The truncated quadratic model (REF ) can be reformulated as the following Geman-Reynolds model [1]},
\(\inf _{u \in X, b \in Z} L_{GR}(u , b ) : = D(u)+\frac{\lambda }{2} \int _{\Omega }\left[ b(\frac{\mu }{\lambda } |\nabla u |^2- 1) + I_{\lbrace 0\le b \le 1\rbrace }(b ) +1\right] \mathrm {d}\sigma ,\) 
